Switch actuating device with preadjusted air resistance



July 17, 1962 J. A. GAYLORD 3,045,076 SWITCH ACTUATING DEVICE WITH PREADJUSTED AIR RESISTANCE Filed Dec. 29, 1958 INVENTOR. JOHN A. GAYLORD B I, I

ATTORNEY.

United States Patent 3,045,076 SWITCH ACTUATING DEVICE WITH PRE- ADJUSTED AIR RESISTANCE John A. Gaylord, San Rafael, Calif., assignor to H. Koch & Sons, Corte Madera, Califi, a partnership Filed Dec. 29, 1958, Ser. No. 783,382

' 7 Claims. (Cl. 200-34) This invention relates to a switch actuating device.

In connection with switch actuators where there must be a predetermined interval between the release of the switch actuator and the actuation of the switch and where accuracyrof timing to seconds or fractions thereof is of importance, diificulty arose by the varying air resistance to the switch actuator under difierent atmospheric or air pressure conditions.

The primary object of this invention is to accurately predetermine the air resistance to the switch actuator movement when released so that each actuation is at accurately predetermined timing wherever such accuracy is required.

Another object of the invention is to provide a device whereby the air resistance to a switch actuator can be predetermined to the exact timing of the actuation and where the said preadjustment or predetermination remains substantially constant.

I am aware that some changes may be made in the general arrangements and combinations of the several devices and parts, as well as in the details of the construction thereof without departing from the scope of the present invention as set forth in the following specification, and as defined in the following claims; hence I do not limit my invention to the exact arrangements and combinations of the said device and parts as described in the said specification, nor do I confine myself to the exact details of the construction of the said parts as illustrated in the accompanying drawings.

With the foregoing and other objects in view, which will be made manifest in the following detailed description, reference is had to the accompanying drawings for the illustrative embodiment of the invention, wherein:

FIG. 1 is a cross-sectional view of a switch actuator shown in combination with a conventional switch, the device being shown in the cocked position.

FIG. 2 is a cross-sectional view showing the switch actuator in switch actuating position.

FIG. 3 is an end view of the device, partially in section, the section being taken on lines 3-3 of FIG. 1.

The switch 1 to be actuated is supported by side plates 2 on a base plate or platform 3 which latter projects forwardly and extends transversely from the outside of a cap 4. From the switch I extend the usual conduits 6 through the side of a shield 7. The shield 7 is a generally cylindrical cup the open end of which is provided with a bead 8 which snaps into a circular groove 9 on the outer periphery of the cap 4.

In the center of the cap 4 is a suitably packed bearing hole 11 through which is slida-ble an actuating finger 12. This actuating finger 12 is a cylindrical bar and it has a conical end 13 for engagement with a button 14 projecting downwardly from the switch 1 in the path of the finger 12. The finger 12 is guided in a generally semi-circular guide chamber 16 in the platform 3 so as to hold the finger 12 in registry with the switch button 14. At the base of the conical end 13 is an annular groove 17 in which the button 14 nests after the switch 1 has been actuated. When the finger 12 is retracted into the cocked position shown in FIG. 1 the annular groove 17 is engaged by a locking pin 18 which is inserted into a hole 19 transversely in the platform 3 partly intersecting the guide channel 16. Thus the locking pin 18 holds the finger 12 in cocked position. An end of the pin 18 at one edge of the platform 3 has a suitable engagement member formed thereon, such as an eye 20, whereby the pin 18 can be withdrawn from the platform 3 sufiiciently to clear the annular groove 17 and release the cocked finger12. This eye 20 may be pulled by any suitable means, not shown, for instance by some other timing mechanism for sequence of operation in a device wherein the switch 1 is utilized.

The cap 4 has a cylindrical flange 21 thereon provided with internal threads 22. The cap 4 also has an annular recess 23 around the interior base of the flange 21 to accommodate a suitable packing ring 24.

The finger 12 is actuated by the movement of a piston 26' into the center of which is screwed the threaded end 27 of the finger 12. The piston 26 reciprocates in a cylinder 28 the open end of which is threaded into the threaded flange 21 of the cap 4 so that the outer periphery of the end of the cylinder 28 is sealed by the packing ring 23. A coil spring 29 is nested in a cylindrical pocket 31 in the piston 26 and bears against the end wall 32 of the cylinder 28 so as to urge the piston 26 toward the cap 4. The piston 26 is made airtight by suitable packing rings 33.

The operation of the device as heretofore described involves the steps of pushing the finger 12 inwardly so as to compress the spring 29 until the groove 17 of the finger 12 is registering with the position of the pin 18, where upon the pin 18 is inserted and locks the finger 12 and piston 26 in said cocked position. In order to actuate the switch the pin 18 is pulled out and releases the finger 12 whereby the action of the spring 29 snaps the piston 26 toward the cap '4 and also pushes the finger 12 from the position shown in FIG. 1 into the switch actuating position shown in FIG. 2.

In certain applications the accuracy of the interval between the pulling of the pin 18 and the actuation of the switch 1 is of vital importance for the proper overall operation of certain devices. It was found, however, that under various atmospheric conditions and different atmospheric pressures, there is suflicient variation in the air resistance to the movement of the piston to render the interval between the pulling of the pin and the actuation of the switch inaccurate for such purposes. In order to assure uniform and constant accuracy of operation for which this device can be preadjusted, there is provided in a wall of the cylinder 28 a bypass passage 34, a port 36 of which is adjacent the cap 4. From the other end of the passage 34 inside the comparatively thick end wall 32 of the cylinder 28 extends a metering hole 37 which opens into an enlarged chamber 38 having a port 39 thereof communicating into the cylinder 28 in the rear of the piston 26. The resistance to flow in said system is regulated through the metering hole 37 by a needle valve 41. The needle valve 41 extends from a threaded stem 42 having ahead 43 thereon. The threaded stem 42 is screwed into a threaded portion 44 above the chamber 38. The head '43 has a socket 46 in its top for engagement by a suitable tool for turning the head 43 for the purpose of adjusting the needle valve 41 in the metering hole 37 to a desired position. The head 46 is surrounded by a resilient packing ring 47 in a suitable recess 48 so as to seal the periphery of the head 46 against leakage from either direction and render the system of passages airtight.

In operation, for the preadjustment of the device for a selected interval between the pulling of the pin 18 and the actuation of the valve 1, the needle valve 41 is adjusted in the metering hole 37 to regulate the resistance to the air flow escaping from ahead of the piston 33 when it is pressed by the spring 29 toward the cap 4 and the interval is measured. If the interval is too short, then to prolong the interval the valve 41 is further inserted to reduce the metering hole 30 thereby to increase resistance to the motion of the piston 26 or vice versa. This adjustment is made until the switch actuation is at the selected interval. Then the device is installed in its operative position and retains its adjustment, and operates at the selected interval irrespective of changes of atmospheric pressure around the instrument or device. The switch will be actuated always accurately at the selected interval after the pulling of the locking pin 18.

I claim:

1. In a switch actuating mechanism, a cylinder, a piston working in said cylinder, a switch actuating finger extended from one side of said piston through an end of said cylinder, a spring between the other side of said piston and the other end of said cylinder normally to urge said piston in the direction toward which said finger extends, means outside said end of said cylinder adjacent said finger to hold a switch in operative relation in the path of movement of said finger, releasable means to lock said finger and said piston in cocked position with said spring under tension; a closed system of passages intercommunicating the end of said cylinder at said finger with the other end of the cylinder at said spring, a metering device interconnected in said system of passages to predetermine the rate of fiow in the system and the resistance to the piston mvement when said locking means are released, and means accessible from the outside of said cylinder to adjust said metering device.

2. In a switch actuating mechanism, a cylinder, a piston working in said cylinder, a switch actuating finger extended from one side of said piston through an end of said cylinder, a spring between the other side of said piston and the other end of said cylinder normally to urge said piston in the direction toward which said finger extends, releasable means to lock said finger and said piston in cocked position with said spring under tension; a closed system of passages intercommunicating the end of said cylinder at said finger with the other end of the cylinder at said spring, a metering device interconnected in said system of passages to predetermine the rate of flow in the system and the resistance to the piston movement when said locking means are released, and means accessible from the outside of said cylinder to adjust said metering device, and a platform extended outwardly from said cylinder for guiding said finger, said releasable locking means including a locking pin extended in said platform transversely of said finger and keeper means on said finger for engagement with said locking pin.

3. The switch actuating mechanism defined in claim 2,

and bracket means on said platform for supporting the switch to be actuated in operative relation to said finger.

4. The switch actuating mechanism defined in claim 1, said metering device being in said other end of said cylinder at said spring and including a metering hole in said last mentioned end, a needle valve in said last mentioned end, a head of said valve being adjustably fastened in said last mentioned end to adjust the extent of opening said valve.

5. :In a mechanism for actuating a switch at a precisely predetermined speed, comprising a bracket cap on which the switch is mounted, an airtight cylinder mounted on the bracket cap so that said bracket cap forms an end of the cylinder, a piston in said cylinder, a

spring between the other end of the cylinder and the piston for moving the piston to said bracket cap, a switch actuating element extended from said piston to and through said bracket cap, said bracket cap having an airtight bearing aperture therethrough to guide said actuating element to said switch, releasable means on said bracket cap to lock said actuating element when said piston is adjacent to said other end of the cylinder and when said spring is under tension stored by the withdrawal of said piston toward said other end of the cylinder, said cylinder having a first port at a side thereof near said bracket cap and a second port in said other end, a metering chamber in said other end of the cylinder communicating with said second port, a passage in said cylinder extended from said first port to said metering chamber to communicate flow from ahead of the piston through said first port to said metering chamber and through said second port into the cylinder beyond the piston, an adjustable metering device to predetermine the rate of flow from said first port to said second port, and adjusting means in said other end of said cylinder accessible from the outside of said cylinder to adjust said metering device to the selected speed of switch actuation.

6. The invention defined in claim 5 wherein said metering device is a needle valve, and said adjusting means including a threaded portion on said needle valve, said other end of said cylinder having a threaded socket therein for said threaded portion of said needle valve and having an outer socket extended from the outer periphery of said cylinder to said threaded socket, an adjusting head on said threaded portion and in said outer socket being accessible for turning from the outside of said cylinder, and packing means to render said outer socket airtight around said adjusting head.

7. The invention defined in claim 5, and a platform on the outside of said bracket cap for mounting said switch, said platform having a guide formed therein for guiding said actuating element to said switch, said platform having a transverse lock channel intersecting said guide, said releasable means including a pin inserted into said lock channel, and the projecting portion of the actuating element having a contour fitting over said pin in said lock channel when said piston is in said withdrawn position to coact with said pin for locking said piston in said withdrawn position against the stored tension of said spring.

References Cited in the file of this patent UNITED STATES PATENTS 968,468 Halbleib Aug. 23, 1910 1,167,132 Teetor Jan. 4, 1916 1,768,949 Denison July 1, 1930 1,955,565 Schmidt et al. Apr. 17, 1934 2,367,799 Robinson Jan. 23, 1945 2,389,856 Jones Nov. 27, 1945 2,436,470 Fleming Feb. 24, 1948 2,441,501 Miller May 11, 1948 2,514,747 Daniels July 11, 1950 2,717,288 Heintz Sept. 6, 1955 2,730,354 Burris Ian. 10, 1956 2,804,513 Oppel Aug. 27, 1957 

